BEIJING, Aug. 11 (Xinhua) -- Prosecutors have approved the arrest of four employees of the Anglo-Australian mining giant Rio Tinto Ltd. on charges of trade secrets infringement and bribery, according to a statement of China's Supreme People's Procuratorate late Tuesday.

Preliminary investigations have showed that the four employees, Stern Hu, Liu Caikui, Ge Minqiang and Wang Yong, had obtained commercial secrets of China's steel and iron industry through improper means, which had violated the country's Criminal Law, according to the statement.

Prosecution authorities also found evidence to prove that they were involved in commercial bribery.

Investigations have also revealed that there were suspects in China's steel and iron enterprises who were providing commercial secrets for them.

The four were detained in Shanghai in early July on charges of stealing China's state secrets.

Stern Hu, an Australian citizen of Chinese origin, was general manager of the company's Shanghai office and was in charge of the iron ore business in China.

Hu was a long-standing employee of Rio Tinto and had lived in Shanghai for a number of years with his wife, who is also an Australian citizen.

The other three, who also worked in the Shanghai office, are Chinese employees of the company.